Apparatus for rolling cylindrical surfaces on a workpiece

ABSTRACT

A hollow rotatable drive shaft has an annulus of elongated workpiece-engaging rollers which are rotatable about the axis of the shaft and which are each inclined to this axis, the surface to be rolled being adapted to be located within the annulus. A roller cone surrounds and guides the rollers and an arrangement for advancing the rollers and cone axially forwardly is provided. Abutments engage the rollers when the same have performed a predetermined axial movement to prevent further such movement while permitting continued axially forward movement of the cone. In response to such forward axial movement of the cone a spring arrangement located in the shaft exerts via the cone a force upon the rollers which counters a rearwardly directed axial force emanating from the rollers.

[ June 11, 1974 APPARATUS FOR ROLLING CYLINDRICAL SURFACES ON A WORKPIECE Primary ExaminerLowell A. Larson Attorney Agent, or FirmMichael S. Striker [75] Inventor: Bernhard Kunze, Erkelenz, Germany ABSTRACT [73] Assignee: Wilhelm Hegenscheidt Kommanditgesellschaft, Erkelenz, Germany A hollow rotatable drive shaft has an annulus of elongated workpiece -engaging rollers which are rotatable 22 Filed: Oct. 11, 1972 21 Appl. NOJ 296,535

about theaxis of the shaft and whichare each inclined to this axis, the surfaceto be rolled being adapted to be located within the annulus. A roller cone surrounds [30] F i Application Priority Data and guides the rollers and an arrangement for advanc- Oct. 13, 1971 ing the rollers and cone axially forwardly is provided. Abutments engage the rollers when the same have Germany............................ 2150896 performed a predetermined axial movement to pre- [521' US. Cl. 72/121, 29/90 R 1 vent further such movement while permitting continued axially forward movement of the cone. In re- B2ld 22/14 72/121; 29/90 R Int.

Field of sponse to such forward axial movement of the cone a ['56] References Cited spring arrangement located in the shaft exerts via the UNITED STATES PATENTS cone a force upon the rollers which counters a rearwardly directed axial force emanating from the rollers. Koppelmann........................... Koppelmann 6 Claims, 3 Drawing Figures APPARATUS FOR ROLLING CYLINDRICAL SURFACES ON A WORKPIECE BACKGROUND OF THE INVENTION The present invention relates to the rolling of surfaces on a workpiece, and more particularly to the smooth-rolling of a cylindrical surface on a workpiece.

It is already known from the prior art to roll the cylindrical surface on a workpiece, so as to make it completely smooth. The prior art provides for advancing the rollers axially of the cylindrical workpiece, an approach which is used if the elongation of the cylindrical surface is relatively long. The so-called gashing method of rollingcylindrical surfaces on workpieces is used where the axial extension of the surface is short, for instance at seats for journals or the like. The consideration behind this is to produce beneath the roller tools as high as possible a specific surface pressure at an effective roller pressure which should be as small as possible. When the rollers are advanced it is attempted to achieve this by using rollers which are as small as possible and to have so-called drop-shaped contact with the workpiece, whereas in the gashing. method a line contact between tool and workpiece is present. If the pressures exerted by the tools are high, such line contact frequently becomes converted into surface contact and then requires very high pressures to be exerted by the rollers.

Other types of constructions are also known from the prior art and of course it is known to rollingly deform and smooth both cylindrical inner and outer surfaces on the workpiece. The prior art approaches have, however, heretofore always suffered from various disadvantages which are well known to those skilled in the art and are not believed to require a detailed discussion herein. One of these difficulties is that the surface may be actually damaged if the roller pressure becomes too high.

SUMMARY OF THE INVENTION It is a general object of the present invention to overcome the disadvantages of the prior art.

More particularly it is an object of the invention to provide an improved apparatus for rolling a cylindrical surface on a workpiece which is not possessed of the aforementioned disadvantages.

Still more particularly it is an object of the present invention to provide such an improved apparatus which is especially suitable for-effecting such rolling and deformation of concealed surfaces for journals or for sea]- ing purposes.

Another object of the invention is to provide such an apparatus which affords at every part of the surface being rolled an equally good surface quality in terms of the surface smoothness and other characteristics obtained.

'In pursuance of these objects, and of others which will become apparent hereafter, onefeature of the 'invention resides, in an apparatus for rolling a cylindrical surface on a workpiece, in a combination which combines a hollow rotatable drive shaft and an annulus of elongated workpiece-engaging rollers on the shaft and rotatable about the axis of same. Each roller is inclined to the axis of rotation of the shaft and the rollers are arranged to surround the surface to be rolled. A roller cone surrounds and guides the rollers and advancing means is provided for advancing the rollers and cone axially forwardly of the shaft. Abutment means engages the rollers when the same has performed a predetermined axial movement, thus preventing them from continuing the movement but permitting continued axially forward movement of the cone. Spring means in the shaft is operative, and responds to such continued movement of the cone, for exerting via the cone a force upon the rollers which counters a rearwardly directed axial force emanating from the rollers.

The amount of force with which the rollers are pressed into engagement with the surface to be treated can be selected at will, and'by appropriate configuration of the roller cone the force can be strongly magnified so that the forces can be selected and properly controlled.

Of course, the rollers have a relatively significant amount of play in the roller cage which holds them in position. This play may either be the result of manufacturing tolerances or of wear. Because of this there is the possibility that the rollers might not be located in axial parallelism'but be inclined in advancing position, that is inclined to the axis of rotation of the annulus of rollers, thus attempting to advance the roller cone further forwardly in axial direction would increase the force of engagement with the surface to an undesirable level. This could cause the force employed in contact with the surface to become uncontrolled and might result in damage or destruction of the surface. To prevent this the rollers are, in accordance with the present invention, purposely inclined to the rolling plane, that is they are so inclined that due to their engagement with the surface and their inclination, an axial force develops which acts in direction counter to their intended axial advancement. As a result, appropriate direction of rotation causes the roller cone to be advanced counter to the force applied. Of course, the tools (the rollers) need not rotate alone, but the workpiece upon which they act may also be made to rotate.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following descripiton of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIGS la and lb are somewhat diagrammatic axial sections illustrating an apparatus according to the present invention; and

FIG. 2 is a somewhat diagrammatic fragmentary detail view illustrating a feature of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In discussing the drawing in detail, it will be noted that in FIG. 1 the right-hand side shows the apparatus in the position which it assumes when it becomes initially engaged with the workpiece but before rolling operation is begun, whereas the left-hand side shows the apparatus in the position corresponding to the end phase of the rolling operation. The workpiece is designated with reference numeral 1, having a recess 2 provided with a projection 3 the outer circumferential surface of which is to be rolled smooth.

The apparatus hasa shaft 4 which may be engaged in a chuck of an appropriate tool and is advanced axially thereby. This assumes that the tool is being rotated; if the tool is stationary then the shaft 4 is both advanced and rotated.

The end portion of the shaft 4 which is the lower end portion in the drawing carries an element 5 which is axially movable but is not rotatable with reference to the shaft 4. The element 5 carries the roller cone 6 which guides on its inner circumferential surface the conical rollers 7 which rotate between'the outer circumferential surfaceof the projection 3 of the workpiece l and the roller cone 6, abuting the inner circumferential surface of the latter.

Rollers 7 are guided further and mounted in a roller cage 8 which is subject to the biasing action of spring 9 and which is axially displaceable on the element 10. The latter is under the biasing action of the spring 11 which turnably abuts the bolt 14 via the tur'nable component l2 and the ball 13. A shoulder 15 on rollers 7 contacts the element during axial movement of the rollers 7 and limits this movement to a predetermined amount. The rollers 7 are inclined to the central axis of rotation in the rolling plane of an angle which is forwardly inclined with respect to the direction of rotation. A bore 16 is provided in the shaft 4, and in this bore the element 5 is shiftably accommodated, being retained by the threaded sleeve 17 which also serves to delimit movement of the spring 18 which is mounted in the interior of the shaft 4 and which can have its tension varied by nut 19.

in operation, the apparatus is placed with the element 10 onto the workpiece which rotates in the direcvents further axial advancement of the rollers 7. However, the shaft 4 with the cone 6 continues axial advancement until the cone 6. contacts the rollers 7 and is prevented from further movement. Additional movement of the apparatus in downward direction in FIG. 1 causes the member 5 to become displaced from the sleeve 17 which delimits its movement, so that the tension of the spring 18 is released and can be transmitted via the cone 6 to the rollers 7. This direct transmission of the spring force causes the rollers 7 to be pressed against the surface of the projection 3.

- As FIG. 2 shows particularly clearly, the rollers? are inclined in their cage 8 to the direction of rotation of the workpiece by the angle 20, so that an axial component of the rolling force is obtained which acts counter to the direction of advancement of the shaft 4 and acts spring 16.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions dif' fering from the types described above.

While the invention has been. illustrated and described as embodied in an apparatus for rolling cylindricalsurfaces of a workpiece, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt itfor various applications without omitting features that. from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptions should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

I claim:

1. In an apparatus for rolling a cylindrical surface on a workpiece, a combination comprising a hollow rotatable drive shaft; an annulus of elongated workpiece engaging rollers on said shaft and rotatable about the axis of the same, each roller being inclined to the axis of rotation of said shaft and said rollers being arranged to surround the surface to be rolled; a roller cone surrounding and guiding said rollers; advancing means for advancing said rollers and cone axially forwardly of said shaft; abutment means for engaging said rollers when the same have performed a predetermined axial movement, while permitting continued axially forward movement of said cone; andv spring means in said shaft and operative, in response to said continued movement of said cone, for exerting via said cone a force upon said rollers which urges said rollers radially inwardly of said annulus into engagement with the surface to be rolled.

2. A combination as defined in claim 1; further comprising biasing means acting upon all of said rollers in axially forward direction.

3. A combination as defined-in claim 2, further comprising a roller cage guiding said rollers for rolling movement.

4. A combination as defined in claim 3, wherein said roller cage centrically surrounds the axis of said shaft, said biasing means acting upon said cage and said abutment means being at least in part provided on said cage.

5. A combination as defined in claim 4, wherein sai rollers each also have an abutment arranged to cooperate with said abutment means.

6. A combination as defined inclaim 5, wherein said rollers are arranged in said cage at angles so inclined to said axis that said rollers, when acting upon a workpiece surface, produce an axially rearwardly directed force. 

1. In an apparatus for rolling a cylindrical surface on a workpiece, a combination comprising a hollow rotatable drive shaft; an annulus of elongated workpiece engaging rollers on said shaft and rotatable about the axiS of the same, each roller being inclined to the axis of rotation of said shaft and said rollers being arranged to surround the surface to be rolled; a roller cone surrounding and guiding said rollers; advancing means for advancing said rollers and cone axially forwardly of said shaft; abutment means for engaging said rollers when the same have performed a predetermined axial movement, while permitting continued axially forward movement of said cone; and spring means in said shaft and operative, in response to said continued movement of said cone, for exerting via said cone a force upon said rollers which urges said rollers radially inwardly of said annulus into engagement with the surface to be rolled.
 2. A combination as defined in claim 1; further comprising biasing means acting upon all of said rollers in axially forward direction.
 3. A combination as defined in claim 2, further comprising a roller cage guiding said rollers for rolling movement.
 4. A combination as defined in claim 3, wherein said roller cage centrically surrounds the axis of said shaft, said biasing means acting upon said cage and said abutment means being at least in part provided on said cage.
 5. A combination as defined in claim 4, wherein said rollers each also have an abutment arranged to cooperate with said abutment means.
 6. A combination as defined in claim 5, wherein said rollers are arranged in said cage at angles so inclined to said axis that said rollers, when acting upon a workpiece surface, produce an axially rearwardly directed force. 